SpaceX launch delayed again, likely bumps Antares launch at Wallops

SpaceX scrubbed its resupply launch from Cape Canaveral to the International Space Station at the last minute Monday because of a helium leak in its first-stage rocket, which makes the May 6 resupply launch from Wallops Island even less likely, experts say.

The next earliest launch window for SpaceX would come at 3:25 p.m. Friday, NASA said, although SpaceX noted the weather on that date "isn't ideal."

It's the latest in about a month of delays for SpaceX, and it pushes the launch of Orbital Sciences Corp.'s Antares rocket to send cargo from Virginia's Mid-Atlantic Regional Spaceport (MARS) to the ISS into mid-June, experts say.

SpaceX had hoped to launch at 4:58 p.m. Monday, despite the recent failure of a backup computer outside the station. NASA had said the station still had enough redundancy to accommodate the mission.

Because of this most recent delay and other unrelated issues, now Virgina-based Orbital will likely have to wait at least another month to make its second resupply mission, called Orb-2, from MARS, located at the NASA Wallops Flight Facility on the Eastern Shore.

Orbital spokesman Barron "Barry" Beneski explained the SpaceX cargo ship must remain at the space station for 28 days to accommodate various science experiments. Then a scheduled crew rotation will leave the station understaffed just as a shift in the station's orbital alignment with the sun in late May will leave it under-powered.

It all conspires to force NASA to reschedule Orbital's Antares rocket launch to sometime after June 9, he said.

The Antares will carry a Cygnus supply ship on a mission to bring more than one and a half metric tons of cargo to station astronauts. According to Orbital, the Cygnus is already fully integrated with the booster at Wallops and packed with more than half its payload.

Orbital has a $1.9 billion commercial contract with NASA to make eight cargo runs to the space station. The first was in January, and the rest are supposed to launch from Wallops through 2016.

SpaceX is the second private U.S. company with a commercial contract to resupply the ISS. Its Dragon supply ship is to carry needed groceries and supplies for station astronauts.

The craft was also reported to be loaded at the last minute with a gasket material to enable astronauts to repair the external backup computer during a spacewalk set for April 22.